Gas turbine engines are used to power aircraft, watercraft, power generators, and the like. Gas turbine engines typically include a compressor, a combustor, and a turbine. The compressor compresses air drawn into the engine and delivers high pressure air to the combustor. In the combustor, fuel is mixed with the high pressure air and is ignited. Products of the combustion reaction in the combustor are directed into the turbine where work is extracted to drive the compressor and, sometimes, an output shaft, fan, or propeller. Left-over products of the combustion are exhausted out of the turbine and may provide thrust in some applications.
Turbines typically include alternating stages of static vane assemblies and rotating wheel assemblies. The rotating wheel assemblies include disks carrying blades that are coupled to the disks. When the rotating wheel assemblies turn, tips of the blades move along blade tracks included in static shrouds that are supported around the rotating wheel assemblies.
Interest in improving efficiency and reducing emissions of gas turbine engines is driving demand for components that can withstand high temperature environments. One limitation to improving the efficiency and reducing the emissions of some gas turbine engines is the temperature capability of hot section components (for example, but not limited to turbine vanes, blades, and blade tracks). Materials able to withstand high temperature environments, such as ceramic-based materials, may be considered for use in gas turbines but present design and manufacturing challenges.